The presently disclosed embodiments relate generally to an in-situ method to prevent pigmented ink from settling in long running-time environments as well as environments where the ink jet printer is in a standby mode. Micro-magnetic particles are introduced into an ink reservoir and/or an ink passageway and a tunable magnetic field is generated which results in an establishment of chaotic motion of the micro-magnetic particles throughout the ink mixture and a better dispersed ink product.
Uniform and homogeneous pigmented ink is known to suffer from becoming heavily layered mixture due to ink “settling” upon the passage of time. The ink “settling” yield unacceptable defects on image density. The ink “settling” yields unacceptable defects in the printer hardware, such as clogging of jetting nozzles. Accordingly, stable pigment dispersion in ink is always required in ink jet printing.
Dispersant is used to provide a chemical solution to the pigment dispersion issue in ink. The use of pigment dispersants, although practiced in the community to prompt pigment dispersion, is not favorable due to its negative impact on ink flowability and drop formation during the jetting process. It is a passive method to deal with ink “settling.” Dispersants are still challenging to become an effective solution for longer life. At present, an amount of physical solutions have been widely practiced.
There are physical or mechanical solutions that are widely practiced. These mechanical solutions include stir bars, raised fluid exits and pumping assemblies. For example, U.S. Pat. No. 7,643,776 describes these mechanical solutions.
However, none of these solutions come with an economical advantage, an acceptable relief of system integration (design, manufacturing and use), and performance maximization. Performance maximization means that there is less material waste and higher efficiency.
Accordingly, a need exists for a system to be developed that prevents ink from settling and keeps the ink having uniform dispersion during a long running time. More specifically, a need exits to develop an effective and continual mixing method that is low cost, highly effective, compact in size and results in high flexibility.
Further, there remains a need to develop a dispersion technology which reduces processing time and cost, without sacrificing benchmark material properties (e.g., small size and narrow particle size distribution).